lecture 9 fossil fuel

lecture 9 fossil fuel - 2/14/09
 GEOL 103 Spring 2009

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Unformatted text preview: 2/14/09
 GEOL 103 Spring 2009 Environment
of
the
Earth
 Lecture 9: Fossil fuels Reading: Montgomery Chapter 14 Humans
Require
Abundant
Energy
 •  Fossil
Fuels
are
energy
stored
in
chemical
 bonds
of
ancient
organic
life
 –  Oil
 –  Natural
gas
 –  Coal
 –  Oil
shale
 –  Tar
sand
 •  When
we
burn
them,
we
are
using
that
 stored
energy
 In
class
poll:
 How
long
will
global
oil
resources
last,
ballpark
 A. 10
years
 B. 50
years
 C. 100
years
 D. 1000
years
 E. There
is
no
oil
leB
 U.S.
energy
consumpFon,
1949‐2001
 1
 2/14/09
 Oil
and
Natural
Gas
 •  Petroleum:
complex
suite
of
chemical
 compounds
including
oil
and
natural
gas
 associated
with
it
 –  Oil:
a
variety
of
heavy
liquid
hydrocarbon
 compounds
 –  Natural
Gas:
gaseous
hydrocarbon
compound
 most
commonly
methane
(CH4)
 FormaFon
of
Oil
and
Gas
Deposits
 •  Organic
maRer,
rich
in
carbon
and
hydrogen,
 accumulate
and
are
rapidly
buried
 •  Prevents
respiraFon
–
improves
the
chance
that
 chemical
energy
will
be
preserved
in
CH2O
 •  Source
rocks
=
organic
rich
sediment
 •  This
is
where
the
process
of
petroleum
starts
 •  Mature
oil
and
gas
deposits
happen
millions
of
years
 later
 FormaFon
of
Oil
and
Gas
Deposits
 •  A
mixture
of
hydrocarbon
products
are
 derived
from
most
oil
fields
 •  The
Fme
and
history
of
the
formaFon
of
the
 energy
deposit
are
factors
 –  Heat
and
pressure
act
to
modify
the
organic
 molecules
 –  Large
organic
molecules
(‘heavy’
hydrocarbons)
 will
be
broken
down
into
smaller
molecules
 (‘lighter’
hydrocarbons)
 Oil
and
Gas
MigraFon
 •  The
solid
organic
maRer
will
be
converted
to
 liquids
and/or
gases
(hydrocarbons)
 •  Liquid
and
gaseous
hydrocarbon
will
migrate
out
 of
the
rocks
in
which
they
formed
 •  The
migraFon
is
required
so
the
hydrocarbon
will
 pool
in
economically
usable
deposits
 •  Reservoir
rocks
for
hydrocarbon
are
overlain
by
 impermeable
caps
that
trap
the
migraFon
of
the
 hydrocarbons,
otherwise,
oil
and
gas
may
keep
 rising
to
the
earth’s
surface
 2
 2/14/09
 Which
is
an
example
of
a
highly
porous
sedimentary
rock:
 A. Shale
 B. Granite
 C. Sandstone
 D. Mica
 E. Slate
 Types
of
petroleum
traps
 3
 2/14/09
 Time
Factor
 •  Very
few
hydrocarbon
deposits
are
found
in
 rocks
less
than
1
to
2
million
years
old
 •  Geologist
suspect
the
process
is
slow
and
 takes
longer
than
a
few
tens
of
thousands
of
 years
 •  Oil
and
Natural
gas
are
nonrenewable
energy
 resources
 •  The
organic
material
falling
to
the
sea
floors
 today
will
not
be
useful
as
petroleum
products
 in
our
lifeFme
 Proven
world
reserves
of
crude
oil
and
natural
 gas,
2002
 hRp://www.spr.doe.gov/dir/dir.html
 STRATEGIC
PETROLEUM
RESERVE
INVENTORY

 


 

 


 

 
CURRENT
SPR
INVENTORY
AS
OF

February
11,
2009
 


 
SWEET
 
SOUR
 


 


 


 
TOTAL
 


 
280.6
million
bbls
 
423.4
million
bbls
 
*
 


 


 
704.0
 


 


 


 


 


 


 


 


 


 


 

 
 
 


 


 Due
to
elevated
security
concerns,
detailed
informaFon
on
 SPR
siteshas
been
removed
from
this
web
site
 ProjecFon
of
Oil
ProducFon
 4
 2/14/09
 Adding
to
the
oil
reserve
 •  ArcFc
NaFonal
Wildlife
Reserve
(ANWR)
 •  EsFmates
range
from
4‐14
billion
barrels

 –  Could
take
~5‐10
years
to
get
oil
into
circulaFon
 –  6
month
to
2
yr
supply
 –  Where
would
oil
go?

Strategic
oil
reserves?
 In
class
poll
 Do
you
think
oil
in
ANWR
should
be
recovered?
 A. 
Yes
 B. 
No
 C. 
Don’t
know
 •  ANWR
is
one
of
a
few
natural
environments
 remaining
 •  Biodiversity
is
high
 •  Fragile
ecosystem,
easily
disrupted
 D. 
Don’t
care
 Enhanced
Oil
Recovery
 •  New
technologies
have
increased
producFon
from
 marginally
producing
fields
 •  Primary
recovery
–
limited
to
original
pumping
 •  Secondary
recovery
–
pump
water
into
reservoir
to
 fill
in
empty
pores
and
buoy
up
more
oil
to
be
 pumped
from
the
well
 •  Enhanced
recovery
–
used
aier
primary
and
 secondary
recovery
techniques
have
depleted
the
 recoverable
oil.

As
much
as
75%
of
the
oil
remains
in
 the
reservoir.
 5
 2/14/09
 Alternate
Natural
Gas
Sources
 •  Geologists
must
look
deeper
into
the
hot
 interior
of
the
earth
for
more
natural
gas
 •  Natural
gas
may
be
dissolved
into
the
water
 found
in
the
rocks
at
depth
 •  This
gas
may
be
recoverable
from
these
 geopressurized
zones
 –  EsFmates
range
from
150
to
2000
trillion
cubic
 feet
 –  These
deposits
will
be
expensive
to
drill
 –  The
gas
is
dissolved
into
very
saline
brines
that
will
 present
an
environmental
risk
 Alternate
Natural
Gas
Sources
 •  Methane
in
methane
hydrate
exists
as
 crystalline
solids
of
gas
and
water
molecules
 •  Found
to
be
abundant
in
the
arcFc
regions
 and
in
marine
sediments
 •  EsFmates
of
over
1300
trillion
cubic
feet
of
 methane
in
methane
hydrate
have
been
 studied
off
the
Carolina
coast
 •  It
is
not
clear
how
we
can
tap
into
this
 potenFal
reservoir
 Methane
Hydrate
 6
 2/14/09
 Oil
Spills
 •  About
10,000
spills
each
year
in
U.S.
waters
 –  15
to
25
million
gallons
of
oil
annually
 •  Sources
of
spills
 –  Oil
tankers
 –  Drilling
accidents
 –  Careless
disposal
of
used
oil
 –  IntenFonal
destrucFon
of
pipelines
 –  A
few
natural
seeps
do
occur
 Exxon
Valdez
 Oil
spill,
March
24,
1989
 7
 2/14/09
 Coal
 •  Provides
about
20%
of
U.S.
energy
supply
 –  More
than
50%
of
U.S.
electric
power
generaFon
 •  FormaFon
of
Coal
Deposits
 –  Coal
is
formed
from
remains
of
land
plants,
not
 from
marine
organisms
 –  Swamp
senngs
ideal
with
abundant
trees
and
 leaves
 –  Requires
anaerobic
condiFons
to
convert
the
 fallen
trees
and
dead
leaves
into
coal
 Coal
Forming
Process
 •  Peat
–
first
combusFble
product
to
form
 –  Forms
at
surface
given
the
suitable
condiFons
 •  Lignite
–
soi
brown
form
of
coal
 •  Bituminous
–
harder
variety
of
coal
 •  Anthracite
–
hardest
variety
of
coal
 –  Harder
coal
gives
off
more
heat
for
a
given
weight
 •  In
general,
the
longer
the
Fme
to
form,
the
higher
the
 grade
of
coal
 –  Coal
is
a
nonrenewable
resource
 •  U.S.
coal
reserves
represent
about
50
Fmes
the
 energy
in
the
remaining
oil
reserves
and
40
Fmes
the
 energy
of
remaining
natural
gas
reserves
 8
 2/14/09
 Coal
Reserves
and
Resources
 •  EsFmated
world
reserves
of
1
trillion
tons
 –  EsFmated
10
trillion
tons
in
total
resources
 •  EsFmated
U.S.
reserves
over
270
billion
tons
 of
recoverable
coal
 –  EsFmated
2.7
trillion
tons
in
total
resources
 LimitaFons
on
Coal
Use
 •  Coal
is
not
clean
 –  To
mine
 –  To
burn
 –  To
handle
 •  Coal
is
not
produced
in
a
usable
form
for
 transportaFon
purposes
 •  Used
for
heaFng
and
electricity
generaFon
 9
 2/14/09
 Environmental
Impacts
of
Coal
Use
 •  Produces
abundant
carbon
dioxide
when
burned
 –  Carbon
dioxide
is
a
greenhouse
gas
 •  Liberates
sulfur
as
sulfur
dioxide
into
atmosphere
 upon
burning
 More
acidic

 –  Acid
Rain:
sulfur
dioxide
is
toxic
and
complexes
with
 atmospheric
water
to
produce
sulfuric
acid
 •  Ash
is
liberated
from
coal
upon
burning
 –  Ash
is
as
much
as
20%
of
the
volume
of
coal
 –  Oien
contains
toxic
metal
such
as
selenium
and
uranium
 •  Coal
mining
poses
further
problems:
safety
and
 environmental
issues
 Coal‐Mining
Hazards
and
Environmental
 Impacts
 •  Underground
mining
of
coal
is
dangerous
and
 expensive
 –  Mines
can
collapse
 –  Miners
contract
black
lung
disease
from
coal
dust
or
 cancer
from
radon
gas
 –  Explosion
occur
from
pockets
of
natural
gas
 •  Strip
mining
exposes
the
coal
to
the
weather
 –  Rain
water
and
air
comes
in
contact
with
sulfur
in
the
coal
 beds
or
waste
rock
–
produces
sulfuric
acid
 •  Coal
mine
reclamaFon
is
expensive
and
Fme
 consuming
 Oil
Shale
 •  Oil
Shale
refers
to
a
waxy
solid
hydrocarbon
 called
kerogen
contained
in
a
sedimentary
 rock
 •  Oil
Shale
is
an
abundant
resource
in
U.S.
 –  About
2
to
5
trillion
barrels
of
shale
oil
 –  Not
yet
cost
effecFve
to
exploit
 –  Problems
remain
to
be
solved:
 •  Technology
requirements
 •  Limited
water
supplies
in
mining
areas
 •  Actual
amount
of
oil
to
be
produced
from
shale
is
not
 clearly
defined
 •  Environmental
concerns
 10
 2/14/09
 Tar
Sand
 •  Tar
Sands
are
sedimentary
rocks
containing
a
 very
thick,
semi‐solid,
tarlike
petroleum.

Tar
 sand
deposits
may
represent
very
immature
 petroleum
deposits.
 •  Oil
shale
and
tar
sand
must
be
mined,
 crushed,
and
heated
to
extract
the
petroleum,
 which
can
then
be
refined
into
various
fuels
 11
 2/14/09
 12
 ...
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This note was uploaded on 06/15/2011 for the course GEOL 103 taught by Professor Lakshmi during the Spring '10 term at South Carolina.

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